21-07-2012, 12:13 PM
ELECTRONIC BICYCLE LOCK
[attachment=28305]
The electronic bicycle lock described
here is a worthwhile alternative for
bicycle owners who want to make
their bicycles ‘intelligent’ at reasonable
cost. One of the benefits of building it
yourself is that the
circuit can be used
for virtually any
make of bicycles.
In the circuit,
input jacks J1 and
J2 are two standard
RCA sockets.
A home-made security
loop can be used to link these
two input points. Around 50cm long,
standard 14/36 flexible wire with one
RCA plug per end is enough for the
security loop.
Fig. 1 shows the circuit of the
electronic bicycle lock. It is powered
by a compact 9V battery (6F22).
Key lock switch S1 and smoothing
capacitor C2 are used for connecting
the power supply. A connected
loop cannot activate IC1 and therefore
the speaker does not sound. When
the loop is broken, zener diode ZD1
(3.1V) receives operating power supply
through resistor R2 to enable tone
generator UM3561 (IC1). IC1 remains
enabled until power to the circuit is
turned off using switch S1 or the loop
is re-plugged through J1 and J2.
Assemble the circuit on a generalpurpose
PCB and house in a small tinplate
enclosure. Fit the system key lock
switch (S1) on the front side of the enclosure
as shown in Fig. 2. Place RCA sockets
(J1 and J2) at appropriate positions.
Now, mount the finished unit in place of
your existing lock (as shown in Fig. 3) by
using suitable clamps and screws.
[attachment=28305]
The electronic bicycle lock described
here is a worthwhile alternative for
bicycle owners who want to make
their bicycles ‘intelligent’ at reasonable
cost. One of the benefits of building it
yourself is that the
circuit can be used
for virtually any
make of bicycles.
In the circuit,
input jacks J1 and
J2 are two standard
RCA sockets.
A home-made security
loop can be used to link these
two input points. Around 50cm long,
standard 14/36 flexible wire with one
RCA plug per end is enough for the
security loop.
Fig. 1 shows the circuit of the
electronic bicycle lock. It is powered
by a compact 9V battery (6F22).
Key lock switch S1 and smoothing
capacitor C2 are used for connecting
the power supply. A connected
loop cannot activate IC1 and therefore
the speaker does not sound. When
the loop is broken, zener diode ZD1
(3.1V) receives operating power supply
through resistor R2 to enable tone
generator UM3561 (IC1). IC1 remains
enabled until power to the circuit is
turned off using switch S1 or the loop
is re-plugged through J1 and J2.
Assemble the circuit on a generalpurpose
PCB and house in a small tinplate
enclosure. Fit the system key lock
switch (S1) on the front side of the enclosure
as shown in Fig. 2. Place RCA sockets
(J1 and J2) at appropriate positions.
Now, mount the finished unit in place of
your existing lock (as shown in Fig. 3) by
using suitable clamps and screws.